Axel gustaf emantjel htotgben



A. G. E. HULTGREN. METHOD OF HARDENING souns 0F REVOLUTION. APPLICATIONFILED JUNE 26. 1917.

1,309, 1 37. Patented July 8, 1919.

UNETE SAT or carton.

*AXEL GUSTAF EMANUEL HULTGREN,

0F GOTTENBORG, SWEDEN, ASSIGNOR T0 CORPORATION OF SWEDEN.

METHOD OF HARDENING SOLIDS OF REVOLUTION.

Specification of Letters Patent.

Patented July 8, 19 19.

Application filed June 26, 1917. Serial No. 177,071.

To all whom it may concern:

Be it known that I, AXEL GUSTAF EMAN- UEL HULTGREN, a citizen of theKingdom of Sweden, residing at Gottenborg, Sweden, have invented new anduseful Improved Methods of Hardening Solids of Revolution, of which thefollowing is a specification.

On hardening bodies in general a deformation of the body to a greater orsmaller extent occurs caused by an uneven cooling of the body.essentially on the following grounds, v1z., (1) that the various partsof the body when immersed into the hardening liquid do notsimultaneously come into contact with the liquid and (2) that during thefollowing cooling operation which always takes place by moving the bodyand the hardening liquid 1n relation to each otherthe cooling of thebody will be stronger on that part of the surface where on account ofthe movements and the shape of the body the circulation of the liquid inrelation to the body idly removed from'the surface of the body. Saiddeformation is especially perceptible and inconvenient on hardeningring-shaped bodies having a comparatively small crosssectional area inrelation to the diameter, as, for instance, the rings of ball and rollerbearings The object of this invention is to prevent the saidinconveniences connected with the hardening of bodies having the form ofsolids of revolution, especially the bearing rings of ball and rollerbearings. For this purpose the invention consists in causing the body tobe hardened to rotate, before it is introduced into the hardeningliquid, and thereupon introducing the body into said liquid in suchmanner that it will rotate therein, and also advance bodily in adirection forming an angle with the axis of revolution of the body.

The speed of rotation of the bodies to be hardened depends upon the sizeof the body, and the rotation may, obviously, be effected in differentmanners and by different means.

The accompanying drawing illustrates a Said uneven cooling arises willbe most intense and on account thereof the vapors will be most rapdeviceadapted for performing the method in question. Figure 1 is in part aside-view and in part a vertical section of said device, and Fig. 2 is aplan-view thereof.

The device consists, substantially, of an inclined track or channel 1supporting the bodies or rings to be hardened, the lower end of whichtrack or channel extends below the surface of the hardening liquid contained in a receptacle 2. The-length of the portion of the track 1located above the hardening liquid depends upon the speed which is to beimparted to the bodies passing down said track. The said portion may, asis shown in Fig. 2, be divided into any number of grooves or slotsseparated from each other. Placed at the lower end of the track in thereceptacle 2 is a basket 3 or the like collecting the hardened bodies,said basket being preferably adapted to be raised out of the hardeningliquid. The distance passed by the bodies in said liquid during therotation should,.preferably, be of such length that the bodies arecooled sufficiently, when reaching the collecting device.

Obviously, the track or channel neednot necessarily extend below thesurface of the hardening liquid, because the rotating movement isimparted to the bodies before reaching said surface. The shape of thetrack shown in the drawing is, however, to be preferred, if the bodies,when hardened, are collected within a rather limited space, as

for instance in the basket shown. Of course,

ball

consisting in causing the body to be hardened to roll along an inclineintd the hardening liquid.

8. A method of hardening bodies having the form of solids of revolution,consisting in imparting a spinning movement to' the bod b causin it toroll alon an incline, bod

y y g g 5 and introducing it, while spinning, into a body of hardeningliquid toward which said incline extends. whereby the body will r0- Intestimony whereof I have signed my name.

AKEL GUSTAF EMANUEL HULTGREN.

